From Sensing to Acclimation: The Role of Membrane Lipid Remodeling in Plant Responses to Low Temperatures.

Low temperatures pose a dramatic challenge to plant viability. Chilling and freezing disrupt cellular processes, forcing metabolic adaptations reflected in alterations to membrane compositions. Understanding the mechanisms of plant cold tolerance is increasingly important due to anticipated increases in the frequency, severity, and duration of cold events. This review synthesizes current knowledge on the adaptive changes of membrane glycerolipids, sphingolipids, and phytosterols in response to cold stress. We delve into key mechanisms of low temperature membrane remodeling, including acyl editing and headgroup exchange, lipase activity, and phytosterol abundance changes, focusing on their impact at the subcellular level. Furthermore, we tabulate and analyze current gycerolipidomic data from cold treatments of Arabidopsis, maize, and sorghum. This analysis highlights congruencies of lipid abundance changes in response to varying degrees of cold stress. Ultimately, this review aids in rationalizing observed lipid fluctuations and pinpoints key gaps in our current capacity to fully understand how plants orchestrate these membrane responses to cold stress.

Apple Fruit Edge Detection Model Using a Rough Set and Convolutional Neural Network.

Accurately and effectively detecting the growth position and contour size of apple fruits is crucial for achieving intelligent picking and yield predictions. Thus, an effective fruit edge detection algorithm is necessary. In this study, a fusion edge detection model (RED) based on a convolutional neural network and rough sets was proposed. The Faster-RCNN was used to segment multiple apple images into a single apple image for edge detection, greatly reducing the surrounding noise of the target. Moreover, the K-means clustering algorithm was used to segment the target of a single apple image for further noise reduction. Considering the influence of illumination, complex backgrounds and dense occlusions, rough set was applied to obtain the edge image of the target for the upper and lower approximation images, and the results were compared with those of relevant algorithms in this field. The experimental results showed that the RED model in this paper had high accuracy and robustness, and its detection accuracy and stability were significantly improved compared to those of traditional operators, especially under the influence of illumination and complex backgrounds. The RED model is expected to provide a promising basis for intelligent fruit picking and yield prediction.

Anion-Driven C-F Bond Activation of Trifluoromethyl N-Aryl Hydrazones: Application to the Synthesis of 1,3,4-Oxadiazoles.

The CF3 group attached to N-aryl hydrazone could be activated upon treatment with a suitable base, thus serving as an excellent C1 unit for the assembly of a series of 1,3,4-oxadiazoles by reaction with hydrazides. The transformation is proposed to proceed via the intermediate formation of a gem-difluorinated azoalkene. Furthermore, this reaction features simple conditions and a broad substrate scope with respect to both trifluoromethyl N-aryl hydrazones and hydrazides.

Comprehensive multicomponent characterization and quality assessment of Shuang-Huang-Lian powder injection using ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry and ultra-high-performance liquid chromatography-quadrupole-Orbitrap-mass spectrometry.

RATIONALE: Shuang-Huang-Lian powder injection (SHLPI) is a well-known modern traditional Chinese medicine formula preparation (TCMFP) widely used to treat acute upper respiratory infections. However, SHLPI is extracted from pure Chinese medicine and administered through an injection, and many adverse reactions have been reported clinically. Therefore, it is necessary to characterize in depth the chemical composition of SHLPI and quantitatively analyze its potential allergenic components. METHODS: In this study, the samples were analyzed using ion mobility ultra-high-performance liquid chromatography-quadrupole time-of-flight-mass spectrometry (UHPLC-QTOF-MS) combined with a self-built database. Furthermore, the parallel reaction monitoring (PRM) model of ultra-high-performance liquid chromatography-quadrupole-Orbitrap-mass spectrometry (UHPLC-Q-Orbitrap-MS) was used to successfully quantify 10 representative bioactive components. RESULTS: Using this strategy 90 compounds were identified, the fragmentation pathways of five representative compounds in the five main components of SHLPI were summarized, and 10 components (neochlorogenic acid, chlorogenic acid, sweroside, forsythiaside A, luteoloside, isochlorogenic acid B, isochlorogenic acid C, baicalin, phillyrin, and baicalein) were determine as the quality markers of SHLPI based on UPLC-Q-Orbitrap-MS. CONCLUSIONS: This work comprehensively characterized the material basis of SHLPI, summarized the cracking laws of representative substances, and quantitatively analyzed 10 potential allergenic components. Therefore, this study could provide a basis for the quality control of SHLPI and the clinical rational use of drugs to reduce its adverse reactions.

Discovery of a Novel Class of Acylthiourea-Containing Isoxazoline Insecticides against Plutella xylostella.

Isoxazoline structures are widely found in natural products and are rich in biological activities. This study discloses the development of a series of novel isoxazoline derivatives by introducing acylthiourea fragments to access insecticidal activity. All synthetic compounds were examined for their insecticidal activity against Plutella xylostella, with results showing moderate to strong activity. Based on this, the structure-activity relationship analysis was carried out via the constructed three-dimensional quantitative structure-activity relationship model to further guide the structure optimization, resulting in the optimal compound 32. The LC50 of compound 32 against Plutella xylostella was 0.26 mg/L, demonstrating better activity than the positive control, ethiprole (LC50 = 3.81 mg/L), avermectin (LC50 = 12.32 mg/L), and compounds 1-31. The insect GABA enzyme-linked immunosorbent assay demonstrated that compound 32 might act on the insect GABA receptor, and the molecular docking assay further illustrated the mode of action of compound 32 with the GABA receptor. In addition, the proteomics analysis indicated that the action of compound 32 on Plutella xylostella was multi-pathway.

Development of ß,ß-Dibrominated Secondary Enamides and Their Application to the Synthesis of 5-Br Oxazoles.

Herein, we report a base promoted dibromination of enamides using CBr4 as a bromine source to provide expedient access to ß,ß-dibrominated secondary enamides. Preliminary synthetic application study shows that these novel products can be readily transformed to 5-Br oxazoles via Cu(I) catalyzed intramolecular cyclization in good yields.

Ultrahigh-performance liquid chromatography coupled to ion mobility quadrupole time-of-flight mass spectrometry profiling and unveiling the transformation of ginsenosides by the dual conditions of citric acid and high-pressure steaming.

RATIONALE: Many methods have been reported for the production of rare ginsenosides, including heat treatment, acid hydrolysis, alkaline hydrolysis, enzymatic hydrolysis, and microbial transformation. However, the conversion of original ginsenosides to rare ginsenosides under the dual conditions of citric acid and high-pressure steam sterilization has rarely been reported. METHODS: In this study, a method involving ultrahigh-performance liquid chromatography coupled to ion mobility quadrupole time-of-flight mass spectrometry was developed for analysis of chemical transformation of protopanaxatriol (PPT)-type ginsenosides Rg1 and Re, protopanaxadiol (PPD)-type ginsenoside Rb1 , and total ginsenosides in the dual conditions of citric acid and high-pressure steam sterilization. An internal ginsenoside database containing 126 known ginsenosides and 18 ginsenoside reference compounds was established to identify the transformation products and explore possible transformation pathways and mechanisms. RESULTS: A total of 54 ginsenosides have been preliminarily identified in the transformation products of PPD-type ginsenosides Rg1 and Re, PPD-type ginsenoside Rb1 , and total ginsenosides, and the possible transformation pathways were as follows: Rg1 , Re → 20(S)-Rh12 , 20(R)-Rh12 ; Rg1 , Re → 20(S)-Rh1 , 20(R)-Rh1 → Rk3 , Rh4 , Rh5 ; Rb1 → gypenoside LXXV; Rb1 → 20(S)-Rg3 , 20(R)-Rg3 → Rk1 , Rg5 ; Re → 20(S)-Rg2 , 20(R)-Rg2 → 20(S)-Rf2 , 20(R)-Rf2 , Rg4 , F4 . CONCLUSIONS: The results elucidated the possible transformation pathways and mechanisms of ginsenosides in the dual conditions of citric acid and high-pressure steam sterilization, which were helpful for revealing the mechanisms of ginsenosides and enhanced safety and quality control of pharmaceuticals and nutraceuticals. Meanwhile, a simple, efficient, and practical method was developed for the production of rare ginsenosides, which has the potential to produce diverse rare ginsenosides on an industrial scale.

Identification of differentially expressed genes, transcription factors, microRNAs and pathways in neutrophils of sepsis patients through bioinformatics analysis.

Sepsis has been recognized to be a life-threatening organ dysfunction caused by the dysregulation of the host response to infections. Our work aims to screen key biomarkers related to neutrophils in sepsis using bioinformatics analysis. For this purpose, the microarray datasets related to neutrophils in sepsis patients were downloaded from the Gene Expression Omnibus (GEO) database. According to the Bayesian test, the Limma package in R was used to screen differentially expressed genes (DEGs). Then, DEGs were uploaded to the DAVID online diagnostic tool for subsequent Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment on the selected DEGs. Next, protein-protein interaction (PPI) network was established based on the selected DEGs using the STRING website and the Cytoscape software. Furthermore, according to the function of the iRegulon plug-in in Cytoscape, our study further predicts and established regulatory networks related to transcription factors and regulatory genes. In addition, the miRWalk2.0 database was used to search for miRNA-DEG pairs, associated with the conduction of intersections of miRNAs predicted by TargetScan, Miranda, miRDB and RNA22 databases. Then, these miRNA-DEG pairs were also displayed in the form of a regulatory network through Cytoscape. Finally, two datasets were selected to verify the screened genes, regulatory factors, and miRNAs, to plot receiver operating characteristics (ROC) curves and compute the area under the curve (AUC) values. The results showed that AKT1, MMP9, ARG1, ETS1 targeting AKT1, and has-miR-124-3p targeting RPS6KA5 may have diagnostic value for patients with sepsis and septic shock. While further experimental studies are required to confirm their role in septic neutrophils.

Compounds with NO Inhibitory Effect from the Rattan Stems of Sinomenium acutum, a Kind of Chinese Folk Medicine for Treating Rheumatoid Arthritis.

Three new alkaloids (1-3), one new diphenyl ether (4) and fifteen known alkaloids (5-19) were isolated from the rattan stems of Sinomenium acutum. Comprehensive analyses of HR-ESI-MS, 1D (1 H and 13 C), 2D-NMR (1 H-1 H COSY, HSQC, HMBC, NOESY), circular dichroism (CD), UV and IR revealed the structures and absolute configurations of these new compounds. The structures of other compounds were determined by comparison of their 1 H and 13 C-NMR data with previous literature reports. By measuring the amount of NO produced, the anti-inflammatory properties of the isolated compounds were studied. The results showed that compounds 4 and 5 had strong NO inhibitory activity.

Impact of COVID-19 on private driving behavior: Evidence from electric vehicle charging data.

The COVID-19 pandemic has given rise to a major impact on traffic mobility. To implement preventive measures and manage transportation, understanding the transformation of private driving behavior during the pandemic is critical. A data-driven forecasting model is proposed to estimate daily charging demand in the absence of the COVID-19 pandemic by leveraging electric vehicle (EV) charging data from four cities in China. It serves as a benchmark for quantifying the impact of the COVID-19 pandemic on EV charging demand. A vector autoregressive (VAR) model is then used to investigate the dynamic relationship between the changes in charging demand and potential influencing factors. Potential influencing factors are selected from three aspects: public health data, public concern, and the level of industrial activity. The results show that the magnitude of the decline in EV charging demand varied by city during the pandemic. Furthermore, COVID-19 related factors such as daily hospitalizations and national confirmed cases are the primary causes of the decline in charging demand. The research framework of this paper can be generalized to analyze the changes in other driving behaviors during the pandemic. Finally, three policy implications are proposed to assist other countries in dealing with similar events and to stimulate the recovery of the transport system during the post-pandemic period.

Additive-Free Copper(I)-Mediated Synthesis of 5- or 6-Brominated 2-Aryl-1H-Indole-3-Carboxylates from α,α-Dibromo ß-Iminoesters.

Additive-free copper(I)-bromide-mediated radical cyclization reactions of α,α-dibromo ß-iminoesters were investigated, enabling the synthesis of a series of 5- or 6-brominated 2-aryl-1H-indole-3-carboxylates in moderate to good yields. The mechanistic study showed that (i) the bromine atom originated from the substrates and (ii) the bromination might be related to a 3-bromo-3H indole intermediate via an electrophilic bromine atom transfer. Furthermore, the practicality of this method was demonstrated by gram-scale synthesis and the potential for product derivatization toward other valuable multisubstituted indoles.

Base-promoted, CBr4-mediated tandem bromination/intramolecular Friedel-Crafts alkylation of N-aryl enamines: a facile access to 1H- and 3H-indoles.

Described here is a general and highly efficient method for the synthesis of 1H- and 3H-indoles. In the presence of CBr4 and a suitable base, the cyclization of N-aryl enamines proceeds with high efficiency. Unlike previous intramolecular cross dehydrogenative coupling (CDC) of the same substrates, this process does not require the use of either a transition metal or a stoichiometric amount of oxidant. This method also features operational simplicity, easy scalability and good substrate tolerability. Control experiments indicate the reactions may proceed in a tandem sequence of bromination and intramolecular Friedel-Crafts alkylation in a simple one-pot procedure.

Phytochemical Constituents and Biological Activities of Plants from the Genus Cissampelos.

Cissampelos is a significant genus comprising of approximately 21 species of the medicinal plants (Menispermaceae). The plants of this genus are used in traditional medicine for the treatment of various ailments such as asthma, arthritis, dysentery, hyperglycemia, cardiopathy, hypertension and other related problems. These plants are rich in bioactive dibenzylisoquinoline and aborphine as well as small amounts of other ingredients. In recent years, the chemical constituents and pharmacological activities of Cissampelos genus have been paid more and more attention due to their diversity. Herein, we compile the chemical constituents and biological activities on this genus, and summarize the 13 C-NMR data of the main bioactive ingredients. All information comes from scientific databases such as Google Scholar, PubMed, Sci-Finder, ScienceDirect, Web of Science and CNKI. It provides valuable data for the future research and development of Cissampelos genus.

Ten New Dammarane-Type Saponins with Hypolipidemia Activity from a Functional Herbal Tea-Gynostemma pentaphyllum.

Gynostemma pentaphyllum (thumb.) Makino is a functional herbal tea commonly used in Asian countries and regions to reduce blood lipid levels. G. pentaphyllum saponin is the main component, but there are still a large number of components with lipid-lowering activity that have not been found. In this study, 10 novel dammarane-type saponins, (1-10) and a known one (11) were isolated from G. pentaphyllum. Ten new compounds were identified and named as yunnangypenosides A-J (1-10), and another known one (11) was also obtained. Their chemical structures were determined by MS, NMR spectroscopic analyses. Moreover, the cytotoxicities on human HepG-2 hepatocellular carcinoma cells of these isolates were evaluated, and the results showed that compounds 1-11 had no obvious cytotoxicity. Finally, all these compounds were evaluated for their lipid-lowering effect by means of the oil red O staining method. Ten compounds could significantly reduce lipid levels except of 2, especially 8 exhibite the strongest hypolipidemia activity.

Investigation of the Assembly Behavior of an Amphiphilic Lipopeptide at the Liquid Crystal-Aqueous Interface.

In this article, we designed an amphiphilic lipopeptide molecule, 5(6)-carboxyfluorescein-KKKKKKSKTK-Cys(C12H25)-OMe (FAM-lipopeptide-C12), and studied its assembly behavior at the 4-cyano-4'-pentylbiphenyl (5CB)-aqueous interface. The ordering transitions of liquid crystals (LCs) revealed that FAM-lipopeptide-C12 can assemble at the LC-aqueous interface (both planar and curved interfaces). The assembly can be destroyed by adding trypsin, which catalyzes the hydrolysis of lipopeptides. Fluorescence measurements further confirmed the assembly and deassembly behavior of FAM-lipopeptide-C12 at the LC-aqueous interface. Overall, our work provides a general method for the construction of a biointerface by directly assembling amphiphilic lipopeptides at the LC-aqueous interface, which can potentially be used in selectively detecting the activity of specific enzymes and other biomolecular interactions.

Identification of Vibration Events in Rotating Blades Using a Fiber Optical Tip Timing Sensor.

The blade tip timing (BTT) technique has been widely used in rotation machinery for non-contact blade vibration measurements. As BTT data is under-sampled, it requires complicated algorithms to reconstruct vibration parameters. Before reconstructing the vibration parameters, the right data segment should first be extracted from the massive volumes of BTT data that include noise from blade vibration events. This step requires manual intervention, is highly dependent on the skill of the operator, and has also made it difficult to automate BTT technique applications. This article proposes an included angle distribution (IAD) correlation method between adjacent revolutions to identify blade vibration events automatically in real time. All included angles of the rotor between any two adjacent blades were accurately detected by only one fiber optical tip timing sensor. Three formulas for calculating IAD correlation were then proposed to identify three types of blade vibration events: the blades' overall vibrations, vibration of the adjacent two blades, and vibration of a specific blade. Further, the IAD correlation method was optimized in the calculating process to reduce computation load when identifying every blade's vibration events. The presented IAD correlation method could be used for embedded, real-time, and automatic processing applications. Experimental results showed that the proposed method could identify all vibration events in rotating blades, even small events which may be wrongly identified by skillful operators.

Chemical Constituents with Inhibitory Activity of NO Production from a Wild Edible Mushroom, Russula vinosa Lindbl, May Be Its Nutritional Ingredients.

Russula vinosa Lindbl is a wild edible mushroom that is usually used for original material of food and soup and has rich nutritional value. What are the nutritional ingredients? In order to answer this question, we investigated the chemical constituents of this wild functional food. Six new compounds (1-6), together with nine known ones (7-15), were isolated from R. vinosa. The six new compounds were named as vinosane (1), rulepidadione C (2), (24E)-3,4-seco-cucurbita-4,24-diene-26,29-dioic acid-3-methyl ester (3), (24E)-3,4-seco-cucurbita-4,24-diene-26-oic acid-3-ethyl ester (4), (24E)-3ß-hydroxycucurbita-5,24-diene-26,29-dioic acid (5), and (2S,3S,4R,2'R)-2-(2'-hydroxydocosanoylamino)eicosane-1,3,4-triol (6). Their structures were determined based on spectroscopic methods including HR-ESI-MS, 1D, and 2D NMR. Moreover, a cell counting kit-8 (CCK-8 kit) was used to screen for the cytotoxicity of compounds 1-5 and 7-13 on mouse macrophage RAW 264.7 cells. The results showed that compounds 1-5 and 7-13 had no obvious cytotoxicity. In addition, the inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated mouse macrophage RAW 264.7 cells were evaluated. Compounds 1, 3, 4, 7, 12, and 13 showed moderate inhibitory activity on NO production.

Metal- and base-free synthesis of functionalized α,α-difluoroimines via electrophilic fluorination of N-substituted enamines.

A metal- and base-free synthesis of functionalized α,α-difluoroimines is presented. The reaction features mild conditions, high E/Z control and broad functional group tolerance. The utility of the products was demonstrated through valuable synthetic transformations.

Image fusion via nonlocal sparse K-SVD dictionary learning.

Image fusion aims to merge two or more images captured via various sensors of the same scene to construct a more informative image by integrating their details. Generally, such integration is achieved through the manipulation of the representations of the images concerned. Sparse representation plays an important role in the effective description of images, offering a great potential in a variety of image processing tasks, including image fusion. Supported by sparse representation, in this paper, an approach for image fusion by the use of a novel dictionary learning scheme is proposed. The nonlocal self-similarity property of the images is exploited, not only at the stage of learning the underlying description dictionary but during the process of image fusion. In particular, the property of nonlocal self-similarity is combined with the traditional sparse dictionary. This results in an improved learned dictionary, hereafter referred to as the nonlocal sparse K-SVD dictionary (where K-SVD stands for the K times singular value decomposition that is commonly used in the literature), and abbreviated to NL_SK_SVD. The performance of the NL_SK_SVD dictionary is applied for image fusion using simultaneous orthogonal matching pursuit. The proposed approach is evaluated with different types of images, and compared with a number of alternative image fusion techniques. The resultant superior fused images using the present approach demonstrates the efficacy of the NL_SK_SVD dictionary in sparse image representation.

N-Heterocyclic Carbene Catalyzed Dynamic Kinetic Resolution of Pyranones.

The dynamic kinetic resolution of 6-hydroxypyranones with enals or alkynals through an asymmetric redox esterification is catalyzed by a chiral N-heterocyclic carbene. The resulting esters are obtained in good to high yields and with high levels of enantio- and diastereocontrol. The reaction products are further derivatized to obtain functionalized sugar derivatives and natural products.